Device for controlling the synchronism of two motors.



I. E. THORMEYER.

' DEVICE FOR CONTROLLING THE SYNOHRONISM OF TWO MOTOYIIIS.

' APPLICATION FILED APRJZ, 1911.

1,01 3,331. Pat gated Jan. 2, 1912.

UNITED STATES PATENT OFFICE.

FRANZ EWALD THORMEYER, OF I I IL-IIlfBtlRG2, GERMANY.

nienfxcn roRooNTRoLLING THE sYNoHRoNIsM or TWO MOTORS.

To all whom it may concern:

Be it known that I, FRANZ EWALD THOR- Mnrnn, a citizen and resident ofHamburg, in the German Empire, have invented a new and useful Device forControlling the Synchronism of Two Motors, of which the following is aspecification.

In my prior Patent No. 989,207, dated April 11, 1911, I have described adevice for controlling the synchronous operation of two reproducingapparatus such as a kinematograph and a phonograph, in which speedregulating means and a releasable connection between driving mechanismsare made use of by the aid of which the two apparatus are made torunsynchronously as a rule and when any disturbance arises one or theother may be regulated with regard to its speed. \Vlien electric motorsare employedit is advisable to use electric means to positively connectthe motors and V to regulate the latter by electric means as Well. Thisis done according to the presentinvention 1n such manner, that theWind'- lngs of the armatures are connected by a special conductor, so asto insure synchronous working of the motors, since by way of thisconductor current passes from one motor to the other as soon as onemotor has the tendency. to run faster than the other. To enable onemotor to be regulated independent from the other, whenever any dis:

turbance arises the said connecting conduc tor is provided with acontact breaker and in the feed conductor a resistance is arranged, insuch manner that either in the supply conductor for the armature or inthat forlthe field-magnet of the motor resistances mayfbe switched in.For thisgpurpose a regulating resistance my be em,

ployed in such manner that it can be used as starting switch for bothmotors and when the armatures of the motors are supplied. with currentseparately it can be used as regulating device for the armature of thesecond motor. In theexampleshown in the drawlng it is assumed, that themotor shown on the left runs at a constant speed, while the other can beregulated, so that it may be allowed to run faster or slower-than theother at will.

13y the term positively connected employed in the following description,I mean connected by a good conductor.

Figure 1 of the drawings is a diagrammatio View of a plant to carry thisinvenwhich the armature of one motor is switched oil "from the main orsupply conductor, so that this motor runs asa synchronous motor to theother, which works as a dynamo. Fig. 3 is an elevation of a regulatingdevice.

The motors a and b are provided with the usual collectors 2 and Z andbesides with special slip-rings e, which are connected one with theother by means of a conductor g, which can be opened an" closed by acontact make and break dc ce or switch f. The motors which connectionwith the feed conductors or line wires (1, cl can be operatedandyegulated se mrately when the connecting conductor is opened. hen themotors are 7 to be started both at the same timeso as to make them runsynchronously they are electrically and positively connected togetherbyclosing the contact breaker 'f and the armature of themotor a isconnected with the starting and regulating.resistance Z: by closing thecontact breaker f in a lead wire If desired the resistance 7 may beomitted and replaced by a simple contact make and break device. \Vhenthe resistance 2' is used, the lead with its contact breaker f may beomitted. In the drawing the line wire (Z is shown disconnected from thearmature of the motor Z) by the regulating lever of the regulator lo,but not so the field-magnet. hen the motors are started and made to runat the desired speed, the synchronous operation may be interruptedduring working, by first taking care that the motor 5 supplied throughthe regulating device in at the same tension as through the resistancei, so that the latter may he s itched off from the connection by opening the Contact breaker 7. Both motors will then continue to runsynchronmisly until the electric connection is interrupted by openingthe contact breaker f. Now the motor b can be regulated so as to runslower or faster by cutting out or in resistances in the regulator 7-:and can finally be regulated so as to again secure synchronism,whereupon the positive connection of the motors is again brought aboutby closing the contact breaker f,

The operation described in'the, last para? graph will be betterunderstood lating device 7: instead'of resistance 2' be if the reguPatented Jan.- 2,1912.

are in parallel y opening t used for starting the motors. In so doing,the contact breaker or switch 1' must be closed. iVhen the device is isswitched in and the contact breaker f-is closed both mo- 5 tors will runsynchronously. hen it is desired to interrupt this synchronism, and toregulate the motor 6 independently from motor -a, care mustbe takenbeforehand to give both motors equal tension. This is done 10 byswitching in the resistance device 2', by moving the lever from theposition shown in the drawing. over all the contacts shown. Now theswitch 1 is opened so as to cut the device k out of circuit of the motora; nevertheless,-the motors are bound to run synchronously for reason ofthe positive co nection by the conductor 9. In order to iii; low themotors to run independently from one another, the last named positiveconnec-- tion is interrupted by opening the contact breaker f, whereuponthe motor 6 can be re ulated independently from motor a by ai of theregulating device It.

.Before the contact breaker f is closed, it is of importance to know,whether at the time synchronism is prevailing and whether no currentpasses over from one motor to the other by the connecting conductor. Forthis urpose the s ace in the conductor 9, created be contact breaker fis bridged by a wire, in which an incandescent lamp m or any otherdevice for instance a "oltmeter or the like is arranged,to allowdifferences of tension to be recognized .or read off; such vdevicehowever must be so constructed, that it itself requires so littlecurrent, that it takes no effect in the runningor synchronism of themotors, that is to say, the device must ofier a suitably highresistance. When 40 the motors do not run. synchrdnously the lamp willbecome momentarily incandescent periodically. so that it can be seenwhether there is still a difference in the. speed of the motors. If forinstance in a certain time the '45/ lamp has become incandescent fivetimes the armature of one motor has made five revolutions more "than theother. flVhen the lamp remains incandescent .ontinuously, withoutglowing stronger periodically, the motors I may run synchronously butthe position of the slip rings 0, that is to say, the position of thepoints of connection of the windin wi h the slip 'ri one with referenceto t e other then issue that the differences in the tension exist.These, differences can be balanced by some suitable means, for instancebya resistance n, which preferably is combined with the contact'breakerin suchmanner that in a certain, position of the breaker leventhisresistance is inserted into the conductor 9-. The action-of thisresistance takes place momentarily, so that a short movement there andback is sufficient to balance the difierence. The resistance also has,the chject-to avoid rushes of current thatjiight cause disturbances totake place when the circuit is closed by the lever f. 1 The resistancehereby has the effect to allow the current to pass by degrees. When thelamp oxtinguishes during the run of the motors they work synchronouslyandno tension exists between the slip rings. The switch f may" then beclosed, as has been explained above.-

Instead of an incandescent lamp or bosidm this lam p other electricsignals or indicating. means may be employed. For instance in Figxf 3 adevice is shown, which is well adapted to be used as indicating device,to

indicate any difference in the speed of the two motors. This deviceconsists of an electromagnet 0, the coils of which bridge the opening ofthe contact breaker f and the rocking armature p of which is connectedwith an anchor g, which is adapted to operate a toothed wheel 7'. On theshaft of this. wheel which is acted upon by a spring there is a hand a,which points to a circular The number of revolutions, which one motormakes more than the other in a certain p0 riod of time can be read otffrom this indicator. ,The current 1' ired by this indicator of courseshould a so be so small, that, I when it is working there is no eflecton the speed of one-motor or the other. Nevertheless, there is aconnection between the two motors which, as will be clearly understoodfrom the foregoing description, is passed by some -current and byclosing the contact breaker f, even if no resistance is present, theconductivity of the conductor g is changed to such extent, that thetension between the motors is changed thereby.

Instead of connecting the armature coils or windings ofthe motors-a andb by one single wire,'two or more wires diii bccmployed. In themodification shown in 2 the connecting conductor consists ofthree wires,having a combined contact breaker the three arms of which are moved at'c same time. The resistance n, which mcy110 be conngcfied with one ofth; wi1 f'e;, can be operate y a s ialarm e si or the indicatnr isfn bebrought in confi tion with one single wire. When in the modificationshown in F ig. 2 the motors are rimning aynchmnously and when the comtact maker? is closed the armature of tho. motor can be switched of fromthe ra istances i and b, so that it is supplied merely by -way of theconnecting conductor by the motor a, which then works as dynamo and runsas synchronous motor to it. The regulation of the speedcan be carriedout in the spamemanner. as described with reference to v 'Instead ofmaking. use of two motors, three or .more can be employed and regu latedthe'same manner. Y

I claim:

e 1. In a device of the character described, 13

the combination with the main conductors, and a plurality of motors inparallel con-- nection therewith, of a connecting conductor between thearmature of the motors,

means to control the conductivity of said connecting conductor and aresistance between the motors and one of the main conductors adapted tocontrol the speed of one motor independent of the other.

2. In a device of the character described, the combination with the mainconductors, and a plurality of motors in parallel connection therewith,of a connecting conductor between the armature of the motors, and meansto indicate the number of revolutions which one motor makes more thanthe other in a certain period of time.

3. In a device of the character described, the combination with the mainconductors, and a plurality of motors in parallel connection therewith,of a connecting conductor between the armature of the motors, a contactbreaker in the connecting conductor,

' a signal in the latter adapted to indicate diiferences of tension andto be short circuited by the contact breaker. A

4:. In a device of the character described,

the combination with the main conductors,

and a plurality of motors in parallel connection therewith, of aconnecting conductor between the armature of the motors, and a contactbreaker in the connection conductor, comprising a circular scale andhand to indicate the number of revolutions which one motor makes morethan the other in a certain period of time.

5. In a device of the character described, the combination with the mainconductors, and a plurality of motors in parallel connection therewith,of a connecting conductor between the armature of the motors, a contactbreaker in the connecting conductor, and a resistance in the latteradapted to be switched in or out.

FRANZ EWALD THORMEYER.

\Vitnesses F. A. MAX KAEMPFF, Ennns'r H. L. MUMMENHOFF.

